This invention relates to a subsea connection unit and more particularly relates to a subsea connection for remotely connecting flow conduits at a submerged location.
As the production of hydrocarbons from offshore deposits moves into deeper waters, the problems of providing the necessary submerged flowlines increase. Included in these problems is that of making the required connections between flow conduits at submerged locations, e.g., (1) connecting flowlines to submerged wellheads, (2) connecting submerged manifolding centers to submerged well heads, and (3) connecting submerged flowlines to other flowlines, etc. Where the water depth reaches that at which divers can no longer effectively operate, such connections must be made either by a submerged work vessel or, more preferably, by a remote connector controllable from the surface.
A typical example of a technique in which it is desirable to remotely connect flowlines at a submerged location is described in U.S. Pat. No. 3,698,348. In such a technique, a length of a flowline or a flowline bundle is to be installed between two submerged flow terminal structures, e.g., between a manifold station and a base for a riser, between a wellhead and a manifold station, between the ends of two previously laid flowlines or flowline bundles, or between any two like structures. The length of flowline or flowline bundle, which may extend for several miles, is assembled onshore and towed to the installation site. With proper buoyancy and tension being maintained on the length of flowline, the ends of the length of flowline are drawn downward into position with reference to the submerged flow terminal structures and are connected thereto.
Where this installation technique is carried out in deep water, it is desirable to use connectors which are capable of being controlled remotely from the surface. Also, since the length of flowline may be installed at time substantially later than that at which the submerged flow terminals are positioned on the marine bottom, it is desirable to have all the necessary actuating mechanisms for effecting the connection located on the ends of the flowline being installed as opposed to being located on the flow terminals. This eliminates the need for maintaining the necessary communication links between the actuating means and the surface for long periods of time before the desired connections are actually made.